Three levels of steel and concrete rise from the ground against a ridge. The front of the house has luxurious split-Travertine walls while the back of the house has expansive glass panels.

The entrance, a glass box crowned by a steel disc, is on the second floor. Walk inside to towering ceilings, steel pillars and smooth floors covered in pricey stone and tile, reflecting the original owners' profession as Portland's leading importer of stone from around the world.

Bob Thompson of TVA Architects describes the stunning structure's design as a highly sculpted piece of architecture sited to open to views of the Cascade mountains while maintaining maximum privacy within Forest Park.

Planning and construction took five years.

"The craftsmanship of the home is executed at the highest level and is a testament to the passion and dedication of the artisans who labored for years to build this work of art," says Thompson, who also credits the results to his firm's collaborative relationship with the owners.

The residence has four bedrooms, four full bathrooms, four powder rooms and 11,399 square feet, which breaks down to $759 a square foot based on the asking price. Annual taxes are $84,000.

The second most expensive home for sale in Portland: One of Oregon's most famous houses, the 1918 Frank J Cobbs House on two acres, which is listed at $5.9 million. The English-style mansion, at 2424 Southwest Montgomery Dr., was designed by renowned Portland architect A.E. Doyle. His client: A lumber baron. The telltale signs of the client's profession: Oak beamed ceilings, paneling, stair railings and carved balusters throughout the 14,335-square-foot house.